The present invention is directed to a clamping chuck used in textile winding machines, i.e. thread-winding machines which are designed to provide multiple winding units, each having a rotatable chucking spindle arrangement to receive and hold a bobbin carrier such as a cardboard spool tube or the like in order to take up a thread or yarn at relatively high speeds.
More particularly, the present invention is an improvement over the clamping chucks disclosed in U.S. Pat. No. 4,175,712, issued Nov. 27, 1979, and U.S. Pat. No. 4,223,849, issued Sept. 23, 1980, as a continuation-in-part of the earlier issued but copending U.S. Pat. No. 4,175,712. The disclosures of these patents are incorporated herein by reference as fully as if set forth in their entirety, including any material deemed essential to support the claims or to provide an adequate disclosure of the present invention. Both of these patents contain a similar discussion of the prior art, referring to a chuck with clamping elements operating according to the so-called "freewheeling" or coasting principle as disclosed in U.S. Pat. No. 3,815,836.
In some of the known embodiments, the clamping chuck comprises a clamping spindle and a concentric sleeve surrounding the spindle and having openings through which clamping elements emerge radially to grip the inner wall surface of the bobbin carrier. The clamping elements are positioned in an annular space between the clamping spindle and the sleeve, being supported directly on the spindle, and they extend only slightly in the circumferential direction. For example, in FIGS. 4, 5 and 6 of U.S. Pat. No. 4,223,849, these clamping elements have a relatively narrow width while being elongated to permit a pivotal movement when given an axial thrust. The clamping elements at one circumferential position are synchronously moved in an axial direction by an axially movable annular wall which fills the cross-section between clamping spindle and the sleeve. This annular wall is axially moved by a suitable force transmitting means which acts at the same time on all clamping elements to produce the radial movement which is needed for the clamping and the relaxation.
Although these known clamping chucks have desirable design features, including the self-locking of clamping elements at high speeds, they may in some instances not provide sufficient clamping force, e.g. for high-speed winding of large packages and for high acceleration and deceleration.